Laserfiche WebLink
<br />. <br /> <br />t- f.' - <br />vI,) ,) <br /> <br />" <br /> <br />hydrologic events, precipitation patterns, construction of dams, etc. is important to the understanding of the <br />system in which the endangered fishes have existed over the past 100 years as well an understanding of the <br />effects of man's modification and conceptualization of the expected response of the channel to management <br />changes in the future. Predictive modeling of river response to selected management actions allows <br />formulation of a management plan to achieve desired objectives. Measurement of channel response to <br />management actions during the research period allows detennination of the empirical relationship of channel <br />response to flow and calibration of any modeling efforts to predict effects of river management in the future. <br /> <br />In addition to measurement of cross section change, an understanding of the hydraulic conditions necessary <br />to entrain (and thereby clean) cobble and gravel to prepare spawning sites and the transport mechanisms that <br />are at work fonning low velocity habitat suitable for y-o-y nursery are critical to the development of a river <br />management plan to maximize these two important habitat types. <br /> <br />Data collection and preliminary analysis was initiated in 1992 and has continued through 1996.The basic data <br />collection tasks will continue this year, with concentration on data interpretation and predictive analysis. <br /> <br />Objectives: <br /> <br />1. River Geometrv Analvsis. Detennine short term and long term change in river cross sections at key <br />locations. <br /> <br />2. Suspended Sediment Analysis. Detennine short term sediment transport and compare to long term <br />record. Examine effect of various hydrographs on sediment transport. <br /> <br />3. Cobble/Gravel Entrainment Analysis. Analyze cobble transport conditions at identified and potential <br />spawning locations to detennine flows required to form and maintain spawning bars. <br /> <br />5. Analyze Mechanism of Low Velocity Habitat Formation. Analyze conditions necessary to develop <br />and maintain persistent, high quality backwaters. <br /> <br />Methods: <br /> <br />1. River Geometrv Analysis. The 13 cross-sections surveyed in 1993-1996 will be surveyed pre-- and <br />post-runoff for analysis of annual change and compared to previous surveys to detennine trends. <br />The 10 cross sections established in 1994 in the key detail reaches (RM 0--15, RM 83-89 and RM <br />129-134) will continue to be surveyed as in 1996. Analysis of the change in cross-section geometry <br />and substrate in relation to hydrographic conditions will be completed to provide data necessary for <br />development of the system management plan. <br /> <br />2. Suspended Sediment Analysis. The sediment data collection program initiated in 1992 will continue. <br />Sediment data collected will be compared to long term data to detennine validity of data and <br />comparative effects oftest hydrographs on sediment transport during the runoff period_ <br /> <br />3. Cobble/Gravel Entrainment Analvsis. Potential spawning sites were identified in 1995. These sites <br />as well as sites with similar characteristics were surveyed ad modeled in 1996. An additional survey <br />will be completed in 1997 to characterize response of the sites to differing hydrologic conditions. <br /> <br />45 <br />